I recommend you Good Math by Mark C. Chu-Carroll; it's a fantastic book for programmers who don't know higher math and it explains well how Lambda Calculus work

I recommend you Good Math by Mark C. Chu-Carroll; it's a fantastic book for programmers who don't know higher math and it explains well how Lambda Calculus works. You can also find useful explanations about logic programming, turing completeness, etc. You can take it as an introductory book in Computer Science and read the books mentioned by the author to deepen your knowledge.